A draughtsman has no memory of working on the Canterbury Television building despite more than 100 hours of work being recorded against his name, an inquiry has heard.

Terry Horn worked as a structural draughtsman for the company that designed the building, Alan Reay Consultants, during its construction in 1986.

He told the Canterbury earthquakes royal commission today that he could not recall working on the CTV building, despite 141 hours of his time being logged in time sheets.

"I honestly can't recall the building, full stop," Horn said.

"I would definitely say I didn't do it."

Aspects of the design were inconsistent with his style of draughting, he said.

One example was the "@" sign used in the plans, where he preferred to write "at".

It was possible he did some work on foundation detailing, but it would have taken no more than three days.

Horn said company owner Alan Reay kept "tight control of the office", especially with deadlines, and staff working overtime and weekends was normal.

He recalled Reay's "constant frustration" with council consents officer Graeme Tapper, who he nicknamed "Colonel Tapper", and it was common for Reay to go over his head to chief engineer Bryan Bluck.

Reay was often referred to as "the doctor" because of the importance he placed on his doctorate, Horn said.

"He came across as well-educated and superior," he said.

More than 80 witnesses will be called during the eight-week inquiry, which will cover the initial building consent issued by the Christchurch City Council, the construction and design, identification of a structural weakness in 1990, and the assessment after the September 4 and Boxing Day quakes in 2010.